Dry measuring cups don’t always add up, and it’s mostly the fault of the ingredients. Irregularly shaped or packed ingredients can throw off volume measurements. That’s why we often weigh them. But after several perplexing baking fails, we started to suspect something was amiss with our liquid measurements, too. And this time, the blame is with the cups themselves.

We surveyed 44 liquid measuring cups. More than half produced inaccurate volumes, sometimes even within the same brand. This is due to manufacturing defects when the measurement indications are stamped onto the cups. A 1-cup mark printed even a little higher or lower on the side of the cup can result in significantly more or less volume.

Does it matter? If you’re measuring broth for a soup, not likely. But in instances where precision is crucial (as in many baking recipes), the recipe can be thrown off. In those cases, if your liquid measuring cup is off, it pays to measure your liquids by weight. For example, 1 cup of water, milk or cream weighs 8 ounces. These weights can also reveal the accuracy of your liquid measuring cups. To check, using a digital kitchen scale, add 8 ounces of water to the cup, then check whether the volume matches the indications on the cup. Generally, we found Pyrex, OXO and Norpro to be the most reliably accurate.